1. Field of Invention
The disclosure relates to near field communications (NFC), and more specifically to optimizing gain within an NFC capable device.
2. Related Art
Near field communication (NFC) devices are being integrated into communication devices, such as mobile devices to provide an example, to facilitate the use of these communication devices in conducting daily transactions. For example, instead of carrying numerous credit cards, the credit information provided by these credit cards could be stored onto an NFC device. The NFC device is simply tapped to a credit card terminal to relay the credit information to the terminal to complete a transaction. As another example, a ticket writing system, such as is used in a bus or train terminal, may simply write ticket fare information onto the NFC device instead of providing a ticket to a passenger. The passenger simply taps the NFC device to a reader to ride the bus or the train without the use of a paper ticket.
Generally, NFC requires that NFC devices be present within a relatively small distance from one another so that their corresponding magnetic fields can exchange information. Typically, a first NFC device transmits or generates a magnetic field modulated with the information, such as the credit information or the ticket fare information. This magnetic field inductively couples the information onto a second NFC device that is proximate to the first NFC device, which is received by an antenna of the second NFC device. The second NFC device may respond to the first NFC device by inductively coupling its corresponding information onto an antenna of the first NFC device.
Typically, to process the information received from the second NFC device, the first NFC device demodulates and decodes the received signal with a predetermined gain. In other words, NFC device receiver circuits have traditionally been designed to have a fixed gain. The fixed gain is meant to be a compromise between a maximum gain possible for a poorly-tuned antenna system and a saturation gain that would saturate the receiver in a well-tuned antenna system.
The disclosure will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.